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Lennox · Furnace

E226 High pressure switch failed closed

High severity EL296UHVLennox SL280UHVLennox SL297NV

What the control is telling you

High-fire pressure switch is closed when it should be open.

Applies to: EL296UHV(X) series furnaces (integrated control 103130-XX and 107045-XX)

Likely causes

  • Switch contacts stuck closed
  • Jumpered switch
  • Wiring short

Test and repair steps

  1. Warning: Remove any jumper; the pressure switch must never be bypassed.
  2. The control checks that the pressure switches are open before the inducer starts; a switch closed at that point blocks ignition.
  3. Check high pressure switch operation at the start of a heat call.
  4. Check wiring for shorts.
  5. Measure operating pressure and compare to the set-point tables.
  6. Check the condensate trap and the condensate hose screens at the cold end header box for blockage (power off; twist and pull screens, rinse); prime the trap with 10 fl. oz. (300 ml) of water if dry. If furnace and coil drains are combined, the A/C drain must be vented or the pressure switch will not work properly.
  7. Inspect vent and inducer; replace the switch if contacts are stuck.

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Source: Lennox EL296UHV(X) Unit Information / Service Literature, Table 5 Ignition Control 103130-XX Diagnostic Codes, p.35; Ignition Control 107045-XX Diagnostic Codes table, p.42, Troubleshooting: Heating Sequence of Operation flowchart, p.110-112. Summarized in our own words; check the original manual for your model.

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For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.